Gyro-magnetic compass



Patented Nov. 19, 1940 Grao-MAGNETIC coMPAss Guido Wnsch,Berlin-SteglitzgGeimany, assignor to Askania-Werke A. G., ja corporationof Germany Application ,my 11, 1933, serial No. 679,90:

` In Germany July 15, 1932 16 Claims.

This invention relates to magnetic compasses.r The invention and itsaims and objects will be readilyy understood from. the followingdescription, taken in connection with the accompanying drawing, of oneillustrative Vembodiment of the invention', the true scope of theinvention being Vmore particularly pointed out in the appended claims.

In the drawing: y Fig. 1 is a diagrammatic representation of oneillustrative embodiment of the invention in front view.

Fig. 2 is a diagrammatic representation of. said embodim nt seen fromthe side.

Fig. 3 a diagrammatic lrrepresentation of said embodiment in top view.

Figs. 4 and 5 illustrate in detail the valve 3.

by reason of the precession caused thereby tends to restorethe'gyroscopeto its relatively correct position with respect to themagnetic system.

,In accordance with the present invention how- -'itself, but on thecontrary they exert a reactive Fig. 6 is a fragmentary sectional viewtaken pended magnet system 'very often shows very marked deections ordeviations from the horizontal piane, that is to say, from the surface'25 level of the earth attraction or gravity, in the case of lateralaccelerations, i. e. when the air craft describes a curve. Suchdeviation may. be.

sufllciently, large to entail an error of 2V2 in the compass reading.

To this objectionable feature caused largely by the domination` of thegravity field by the acceleration fields,` there must be added massaccelerations resulting from the' imperfect equilibrium of the needlesystem, the injurious influences of the movements of the air craft bodyabout the magnet system upon the earthmagnetic fleld, as also thecarrying along ofthe magnet system by rotation of the compass hous 40ing, and similar injurious inuenes. All these injurious inuences, owingto the greater speed and therefore greater accelerations inthe case ofair craft have become much greater disturbing factors than washeretofore the case in water navigatin. y j

Attempts have been made to overcome these objectionable features by theuse of various 'exe pedients weil known to the art, but s far asapplicant is aware without success.

The above recited difllculties -and disadvantages are overcome by thepresent invention, which also uses the deviations of the magneticallysensitive direction indicating part or element from the relative correctposition to exert or 55 cause to act upon the gyroscope a force which,

forcethereon the gyroscope -relative to absolute space. 'I'he errorstherefore, heretofore due to r the fact that such forces have theirpoints of application upon thehousing as well as `upon the 20 gyroscope,as above pointed out, are eliminated by the present invention. 4

Another object of the inventionvrelates to the suspension'of the entirecompass and gyroscope system for rotation about a horizontal axis ex 25tending through the centre of gravity of said system, so that the latteris indiiferent to, that' is to say, uninuenced by gravity. This axis,which is preferably the north-south axis, is in turn journaled in asecond support which is rotatable about a vertical axis that isperpendicular to said north-south axis and to the spin axis of thegyroscope. Said reaction or coercive forcesothat is to say, thecompressed air or other compressed iiuid jets should be so adjusted thatno resultant forcewillfbe exerted upon the gyroscopev when thehorizontal axisof oscillation of said gyroscope is in a position atright angles to the direcxtion indicated by the magnet system, i. e.,when said axis is north-south. 4 As a result of the arrangement abovedescribedv the following combined action takes place. e lgyroscopeitself offers a very great resistance to' any'fchange of directioof itsaxis of rotation, so 45 that tlie gyroscope alone exerts a strongquieting action upon the axis of oscillation of-the magnet system. Ifhowever the compass system deviates for any reason from its correctposition, then the force exerted bythe compressed air or other uid jetswhich are thus. rendered operative exerts immediately a correctingaction upon the gy'oscope,

which.' by reason ofrthe precessional movements of the gyroscoperestores the original relative position between s aid magnet system andthe support for the bearings of said magnet system, which,of course, isthe rotor bearing frame Il of the gyroscope.

movements of the magnet needle. n account of s the resistance whichthesgyroscope opposes to any change of direction, the tipping force musthave suilicient strength in order to cause said gyroscope to precess. Asimple displacement of the magnet system occasioned by a brief acci:-dental disturbing influence will not sufilce for this purpose, becausethe magnet system would-immediately in such case return to its originalposition. or swing'beyond it, which would result in a contrary action Abrief pendulating of.` the magnet system about the zero position wouldtherefore be without any effect whatever. As a consequence the gyroscopewould not begin to precess, except in the case of a Swinging movement ofthe magnet system in one direction occasioned by an'actual change ofdirection. so that said swinging movement to one side continues for acertain length of time, 'Ihe northsouth axis must therefore reproducethe actual mean movementsl of the magnet system, that is to say, themean position thereof freed from all disturbing iniluences. Thenorth-south axis therefore produces a well controlled or quietindication of the magnetic meridian A yoke or vertical ring rotatableabout the perpendicular axis and having said north-south axis journaledin bearings therein, would, if provided with a compass card enable acontrolled quiet indication of the magnet meridian, freed' from alldisturbing influences to'be obtained.' Such an`indication of the magnetmeridian could readily be transmitted to additional compass cardslocated at a distance through suitable well-known connections which itis unnecessary to describe here, or it might be reproduced in well-knownmanner for actuating a steering indicator or an automaticcourse-controllingmechanism.

In accordance with the invention novel means may be provided toeliminate or correct any erany suitable kind. In the illustrativeembodi' rors resulting fromiriction in the bearings of Siidperpendicularaxis. Saidmeansmaybeof ment of the invention shown said means com prisesa gravity responsive device and renders operative another force, also-preferably derived from air-Jets or other fluid-:lets acting againstabsolute space and which force-tends to turn horizontal axis in themagnetic meridian. Any

willactasaturningimpulseuponsaidgyroscope which is directedperpendicularly to said vertical braking or ch of the precessionalmovements of said gyroscope about said vertical axis 1axisandtotheaxisofrotationofsaidgyroscope.

and to which impulse said gyroscope endeavors to respond by apreeessional movement about sai'd north-south horizontal axis, causingthe tilt of the gyroscope. In view of the friction in its verticalbearings, a turning exerted upon impulse the gyroscope about saidnorth-south axis would i That is to say. said north-south. axis of thegyroscope -follows continually the not be wholly converted precessionalmovements, so that said gravity responslve'or vertical directionindicating means'connected with the support for the horizontal bearingsof said gyroscope would relatively tilt or swing one way or the other.'I'his swinging movement or tilt can Vbe used in accordance with thepresent invention to render operative said'additional force which tendsto turn the carrier or support in which thej vertical bearings of thenorth-south axis Vare mounted about said vertical axis in the samedirection as the precessional movements of the gyrscope, therebyeliminating said disturbing influence. As however, said gyroscopeopposes to the movements about said perpendicular axis case in theeffects' produced by the true earthl gravity iield. i

In my invention not only does the gyroscope act as a means for averagingout the temporary oscillations of the magnetic'compass, but it alsohelps to prevent such temporary oscillations by stabilizing the magneticcompass about the north-south axis. 'I'his result is secured by mountingthe spindle I2 of the magnetic compass and upper and lower pivots withinthe frame I2a on the rotor bearing frame III, which is 'stabilizedby,the gyro rotor about north-south axis 4 4. Therefore, the verticalaxis of the magnetic compass is not tilted vout of the vertical plane ofthe magnetic-meridian during turns of the aeroplane or dueto othercauses but is stabilized in this plane -by the gyroscope. By this means,many of soIcalled turning errors of the magnetic compass are eliminatedor greatly reduced because the vertical axis of the needle is maintainedin this vertical plane without the necessity for making it heavy on thesouth side of the universal pivot as is usually,done to keep ithorizontal.

Referring now vto the drawing, in the purely illustrative embodiment ofthe invention therein diagrammatically illustrated, a yoke or verticalring 5, which is rotatable about a vertical axis 6 is provided withsockets for the pivot'pins 4 carried by' a support or rotorlbearingframe ID in which the gyroscopic rotor I is journaled in suitber 3 whichcontrols two opposed exit ports 2|,

23 for compressed air or other iluid. When the magneticaxis of themagnet system 2 is in a position parallel to said north-south axis 4 4,and therefore perpendicular to the axis of rotation 9 of the gyroscope,said exit ports 2i, 23 will be equally closed by said valve member 3,but as soon as the axis of said magnet system deviates from its positionparallel to said north-south 'axis 4, theoneorthe other of said exitportswillbecome andin which are provided the ports 2l, 23., It will.-

be apparent that the compressed air escaping reached a horizontalposition, said pendulum 8. or more properly, the `air jet force,controlled thereby, will continue to act about said perpenfrom eitherthe port 2| or the port 23 'in the form a of a jet will exert a reactionforce upon said support I0. This reaction tends to 'throw the axis ofrotation or spin axis 9 of the gyroscope out Lof position and thusproduces -precessional movements of said gyroscope. Similarly thegravity responsive means 8, when in its position of rest, equally closestwo opposed openings from a chamben 8c to which compressed air may besupplied in any suitable manner and from any suitable` source (notshown), vsaid openings being in a a plane perpendicular tio the plane ofsaid yoke 5.

The one or the other of said two openings will nbe uncovered by one legof the divided pendulum B according as the latter swings in the one orthe other direction, and it will be apparent that the jet of airescaping from either one ofssaid openings will exert upon said yoke aforce tending to turn the latter in the one or the other direction, asthe case may be, about the vertical axis 6. The mass of the support I0,the gyroscope If. the magnet system 2, the pendulum 8 and the valvemember v3 and other port controlling means will be so distributed 'thatthe entire system shall be in a position of indifferent equilibrium asregards the north-south horizontal axis 4-4 and in respect to thegravity eld of the earth.

Thenorth-south axis I-l must adjust itself 4in the direction of themagnetic meridian, belcause just as soon as it deviates 4from saiddirec-i of position, said gyroscope immediately begins t'm the tilt andtending to turn the north-south axis back toward its original position.The constructhe gyroscope ,is ho izontal.

tion the axis of the magnet system 2 will no longer dicular axis 6 toeliminate said tilt. It is impossible that the' system should come torest in a position in which the north-south axis coincides with themagnetic meridian, without the axis of rotation 9 of the gyroscopebeing. horizontal, for the reason that in such case the jet of air controll'ed by the pendulum 8 would continue to tend to turn the systemabout the perpendicular axis G, whereupon said magnet system .wouldapparently swing out in the opposite direction, and this would result inan oppositely directed torque about said north-south axis, wherebyadjustment of the axis of rotation 9 of the gyroscope perpendicularly tothe direction of the gravity ileld V would naturally follow.

As all brief scillations of the magnet system and ,of the pendulum 8 arewithout effect owing to the great inertia of the gyroscope, it will beapparentA that said north-south axis does, as a. matter of fact,indicate the direction of' the magnet meridian in a quite invariablemanner, that is to say, continuously without any material deviationtherefrom. i It might happen that 1 the north-south axis should tipabout an axis entire system, such movement would take place be parallelto said north-south axis and conse. v 40 quently one or the other ofsaid airgdischargeports 2|, 23 will be opened more than the other, asJ

above described and Ia-force will thus be exerted upon said bearingsupport I0. As this force tends to tilt the axis of rotation ,9 of thegyroscope out.v

precess in azimuth, and if ther direction of rota-5 tion of thegyroscope-rotor be correctly chosen, a turning movement of the woke 5about the verti' cal axis will be produced. This turning movement vturnsthe support I0 and consequently the escape ports 2l, 23, thus tending toclose the latter. The resistance offered by the friction in the bearingsor by other causes' to the precessional movement of the gyroscopeproduces an actual tipping or tilt of the support I0 about thenorthsouth axis 4.' This causes the pendulum 8 to swing from itsposition which releases, as above described, ajet of compressed air fromone of the openings controlled. by said pendulum, which tends to turnthe ,yoke 5, as therefore the northsouth axis, in the same direction asthat in which the precessionaP force operates, thus eliminatingtion'ancl arrangement of the whole system is suchv that said system willcome to rest in a position such that the north-south axis coincides withthe magnetic meridian d the axis 9 of rotation of l So long as saidnorth-south. axis has not reached ai position wherein it coincides withthe magnetic meridian,

-said compressed air jet controlled by said magnet system willcontinueto operate; and so long as f5 the axis of rotation 9 of the gyroscopehas not perpendicular thereto,'but in suchwcase the axis of themagnet-system will remain in the plane of the magnet meridian, so thatthe vertical component of the magnetic earth eld cannot cause saidmagnet Asystem to deviate. Furthermore in the case of such a tippingmovement of the about anaxis that is parallel to the axis of rotation ofthe gyroscope, so that such tippingl movement would be without eiectupon the gyroscope.

A compass cardcould be alxed in suitable manner to the yoke' 5 and wouldalways indicate without perceptible deviation the true magnetic northdirection. Theapparatus could also be used for reproducing compassindications at a distance, or for indicating direction. For this purposean eccentric disk 1 couldrfor example be mounted upon said vertical axis6 for controlling two compressed air-jets -directed from the nozzles 28,29 toward the opposed nozzles 28a and 29a, respectively, or any othersuch controlling means could -be used for creating a force as soon asthe direction of the north-south axis deviates from a determineddirection of the bearing support 30 for said vertical axis. The forcethus thrown into operation may be used for'ac-,e

tuating a steering indicator which would indicate 55 to the pilot inwhich direction he must steer his air craft in order to `get onto thetrue course.

yOr the force thus created`cou1dv also be used for actuating anautomatic steering mechanism.'

Instead of two sets of jets, a greater number could be controlled bysaid disk fl thus to control or actuate a greater number of,` compasscards or other devices at a distance. It will be apparcould be used totransmit the lmovements of the .herein described withoutdeparting fromthe spirit or essential attributes thereof;;and I therefore -I. am awarethat my present invention mayl ent that electrical or other transmissionmeans be embodied 1n other specific forms than that desire the presentembodiment of said invention -to be .cons`ideredin all respects asillustrative and not restrictive, reference being hadv to the appendedclaims rather than to the foregoing 5 description to yindicate the scopeof the invention@ I claim: y V1. Apparatus'ofl the class describedcomprising, in combination, a support rotatable about two axes, the onesubstantially vertical, lthe other substantially horizontal, lthe latterto coincide with' the magnetic meridian; rotary magnetical- A lysensitive direction-responsive means and a gyroscope carried bysaidsupport, the axis of rotation of Vsaid magnetically sensitive directioresponsive means being substantially; vertical and the axis of rotationof the gyroscope rotor being substantially horizontal and at rightangles to said iirst-named horizontal axis; means to apply a force tothe rotor of said gyroscope tend# ing to tip the vsaine in one directionor the other and cause said gyroscope to precess in acorrespondingazimuthal direction; and means carried `by said support andcontrolled by rotation of said magnetically sensitive means relativelyto'said support on deviation of said first-named horizontal axis fromthe magnetic,r meridian to render said force applying means operative.2. Apparatus oi the class described comprising, in combination, asupport rotatable about two axes', the one substantially vertical, theother substantially horizontal,the latter to coincide with, themagneticmeridian; rotarymagnetically seni sitive direction responsive means anda gyroscope ,35 carried by said support, the axis of rotation of saidmagnetically sensitive direction responsive means being substantiallyvertical and the axis of rotation .of the gyroscope rotor" beingsubstan- I tially horizontal 4and at right angles to said iirst- 40named horizontal axis; means to apply a force to the lgyroscope rotortending to tip the same in .one direction or the other and cause saidgyroscope to precess in a corresponding azimutlialr direction; meanscarried by said support and controlle g by rotation oi' saidmagnetically sensitive means relatively to said support on deviation ofsaid rst-named horizontal axis from the magnetic meridian to render saidforce applying means operative; means to vapply a force l adapted toturn said support about said rstnamed' vertical axis; and meanscontrolled by a 'tipping movement of said gyroscope rotor axis to rendersaid last-named force operative.

.3. Apparatus of the class described compris- 551mg, in combination, aVsupport rotatable about two axes, the one vertical, the otherhorizontal, the latter to coincide withjhe magneticymeridian; rotarymagnetically sensitive direction 'responsive means and a gyroscopecarried by said 6o support, the axis of rotation of, said. magneticallysensitive direction responsive neans being substantially vertical andthe axis of rotation of the gyroscope rotor being substantiallyhorizontal and at right angles to said rst-named hori zontal axis;Fmeans to applyla pneumatic force to the rotor of said gyroscope tendingYto tip the same in one direction or the other and causev the gyroscope`to precess in a corresponding azi"7 muthal direction; and means carriedby said sup- V portand controlled by rotation of said directionresponsive means relatively to said Asupport on deviation of saidiirst-named horizontal axis from the magnetic meridian to render saidpneumatic force applying means operative.

4. Apparatus of the class described comprismtially horizontal and atright angles to said rstnamed Ihorizontal axis; means supplied with tipthe same in4 one direction or the other andcause said gyroscope toprecess in a corresponding azimuthal direction; means carried byl saidsupport and controlled by rotation of said magnetical'ly sensitive'means relatively to said support on deviation of saidiirst-named'horizontal axis from the magnetic meridian to render said Ytive.

5. Apparatus of the class described comprising, in combination, asupport rotatable about two axes, the one vertical and the otherhorizontal. the latter to coincide with the magnetic meridian; rotarymagnetically sensitive direction responsive means and a gyroscopecarried by said support, the axis of rotation Voi.' said indicati' ingmeans being substantially verticaland tbe' axis of rotation of lthegyroscope rotor beingals substantially horizontal andv at right anglesAto said rst-named horizontal axis; kmeans sup- Lplied with pressurefluid and provided with an outlet port therefor, said outlet port beingAar,- ranged to exert fluid raction torques about said horizontal axis;and means carried by said support and controlled by rotation o1 saidmagnetically sensitive means relatively to said support on deviation ofsaid rst-named horizontal axis from the magnetic meridian to open saidport fand allow pressure uid to escape therefrom to impart a movement tosaid gyroscope rotor tending to'tip the same and cause said gyroscope toprecess in an azimuthal direction. ,if y

6 Apparatus of the class described comprising, in combination, a supportrotatable about Ytwo axes, the one substantially vertical and thepressure fluid and provided with an outlet port l therefor, said outletport being arranged -to exert iluid reac'tion`torques about saidhorizontal let port being arranged -to exert fluid reaction torquesabout said vertical axis; andtmean-s controlled by the tipping movementof said support. to open said port' and allow pressure fluid to escapetherefrom and cause the gyroscope to precess about said horizontal axis.v

'7. Apparatus of the class described comprising a support rotatableabout two axes, the one substantially vertical and the othersubstantially horizontal, the latter to coincide with the magneticmeridian; a compas-s carried bysaid support andcomprising a relativelyrotatable magnetically sensitive element and casing 4therefor, theaxisabout which said element is rotatable relatively to its casing beingsubstantially vertical; a gyroscope carried by said support, the axis ofrotation of the rotor of said gyroscope being perpendicular to saidfirst-mentioned axes; means to apply a force to said rotor tending totip the same and cause the same to precess in an azimuthal direction,said force having one point of application on said gyro- .scope and theother on the atmosphere; and means controlled by rotation of' saidelement relatively to its casing to render said force applying meansoperative.

8. Apparatus of the class described comprisf 40 tip the same in onedirection or the other and cause said gyroscope to precess in -acorresponding azimuthal direction; means carried by said support andcontrolled by rotation of said direction responsive means relatively tosaid support on deviation of said iirst-named horizontal axis from themagnetic meridian to render said force applying means operative; meansto applying a torque to said support about said ilrst-named verticalaxis; and pendulous means connected to said support and controlled by atipping movement of said gyroscope spin axis to render saidtorqueiapplying means operative. l 9. A gyro-magnetic compass comprisinga directional gyroscope having a normally horizon- '55 tal east-westdirected spin axis, a gyroscope support, a magnetic element mountedthereon whereby said element becomes stabilized in a north-southvertical plane, and means controlled by a relative displacement of saidsupport and 00 said magnetic element for maintaining the gyroscope spinaxis in predetermined azimuth relation .to the average position of themagneticl element. 10. A gyro-magnetic compass comprising a supportrotatable about a substantially vertical and a substantially horizontalaxis, a gyro rotor with a horizontal spin axis carried by said support,a magnetic element mounted on said support for free turning about asubstantially vertical axis, means to stabilize said magnetic element'to cause said gyroscope to precess to move said 5 supportl into thepredetermined relative position.

11. In a gyro-magnetic compass, the combination, with a directionalgyroscope having a gyro rotor support, of a magnetic element rotatablymounted thereon, laterally and oppositely di- 10 rected air ports insaid support, shutters adapted to be operated by said element foroppositely closing and opening said ports upon relative turning of saidelement and support in azimuth, and means for maintaining differential'air pressure 15 within 'and without said support to cause a flow of airthrough said ports.

12. In a gyro-magnetic compass the combination with a directionalgyroscope having a gyro rotor support, of a magnetic element pivotally20 mounted thereon, and a source of power rendered eiective uponrelative displacement of said element and gyroscope to cause saidgyroscope to follow the average position of said element.

13. A gyro-magnetic compass comprising a gyro 25 rotor, a rotor bearingsupport in which said rotor is journaled on a horizontal spin axis, avertical ring in which said support is journaled about a secondhorizontal axis normal to said spin axis, a magnetic needle pivotedon-said support 30 for movement about a norm'ally vertical axis, andmeans responsive to relative turning of said needle and support inazimuth for applying a torque on said gyroscope about said secondhorizontal axis to precess said gyroscope into agnee- 35 ment with saidneedle.

14.' A gyro-magnetic compass comprising a gyro rotor, a rotor bearingsupport in which said rotor is journaled on a horizontal spin axis, anouter ring in which said support is vjournaled o about a second axis atright angles to said other axis, an outer frame in which said ring isjournaled about a third perpendicular axis, a mag,- netic needle pivotedon said support about a normally vertical axis, means responsive torelative 45 turning of said needle and support in azimuth for applying atorque on said gyroscope about said second axis to precess saidgyroscope into agreement with saidneedle, and means responsive to tiltof ysaid support for applying'a oorrec- 50 tive'torque about thevertical axis. l f

15. A gyro-magnetic compass comprising a gyroscope operating normally ona horizontal spin axis, a. gyro rotor support, a magnetic elementmounted thereon, d means controlled by said 55 magnetic element ormaintaining the gyroscope spin axis in flxed azimuth relation to theaverage position or the magnetic element.

16. A gyro-magnetic compass comprising a gyro rotor, a gyroscope'supportvin whichV said rotor 60 is mounted on a normally horizontal`spin axis. pendulum controlled power means for maintaining. thegyroscope spin axis in a horizontal position, a pivoted magnetic elementmounted on said support, and power means actuated from 65 relativeturning oi' said magnetic element and` support for maintaining thegyroscope spin axis on the magnetic east-west direction.

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